1663217 has 2 divisors, whose sum is σ = 1663218. Its totient is φ = 1663216.

The previous prime is 1663183. The next prime is 1663219. The reversal of 1663217 is 7123661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1079521 + 583696 = 1039^2 + 764^2 .

It is an emirp because it is prime and its reverse (7123661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1663217 - 2⁸ = 1662961 is a prime.

Together with 1663219, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1663219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 831608 + 831609.

It is an arithmetic number, because the mean of its divisors is an integer number (831609).

2^1663217 is an apocalyptic number.

It is an amenable number.

1663217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1663217 is an equidigital number, since it uses as much as digits as its factorization.

1663217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 26.

The square root of 1663217 is about 1289.6577065253. The cubic root of 1663217 is about 118.4812530059.

Adding to 1663217 its reverse (7123661), we get a palindrome (8786878).

The spelling of 1663217 in words is "one million, six hundred sixty-three thousand, two hundred seventeen".